# working institution:School of Mathematical Sciences,Zhejiang University
# author:Kangjie Ding
# date:2022/11/15 21:35
import pygame.image
from pygame.sprite import Sprite

class Ship(Sprite):
    """管理飞船的类"""
    def __init__(self,ai_game):
        """初始化飞船并设置其初始位置"""
        super().__init__()
        self.screen=ai_game.screen
        self.settings=ai_game.settings
        self.screen_rect=ai_game.screen.get_rect()
        #加载飞船图像并获取其外接矩形
        self.image=pygame.image.load("images/ship.jpeg")
        self.rect=self.image.get_rect()
        #对于每艘新飞船，都将其放在屏幕底部的中央
        self.rect.midbottom=self.screen_rect.midbottom
        #移动标志
        self.moving_right=False
        self.moving_left=False

    def update(self):
        """更新飞船的移动"""
        if self.moving_left and self.rect.left>0:
            self.rect.x-=self.settings.ship_speed
        if self.moving_right and self.rect.right<self.screen_rect.right:
            self.rect.x+=self.settings.ship_speed

    def blitme(self):
        """在指定位置绘制飞船"""
        self.screen.blit(self.image,self.rect)

    def center_ship(self):
        """让飞船置于屏幕低端中央"""
        self.rect.midbottom = self.screen_rect.midbottom